Unlike universal flange adapters and couplings, dedicated type flange adapters and couplings are designed for a specific type of pipe, and a dedicated flange adapter can only be connected to pipe with one specific outside diameter, not many different outside diameter pipes.

For large-size pipes (greater than or equal to DN900), it is better to use the dedicated type flange adaptor instead of the universal flange adaptor, because the larger the universal flange adaptor’s range gap is, the larger the gap is between the inner diameter of the body (as below red mark) and the outer diameter of the pipe, and the larger the force that the gland(as below figure No.2) should bears, then the thicker the gland has to be, while the inner diameter of the dedicated type flange adaptor body or dedicated type coupling middle sleeve is designed in accordance with the outer diameter of a specific pipe, so there is no need to consider the insertion of other larger outside diameter pipes, relatively speaking, the gap between the inner diameter of the flange adaptor body or coupling middle sleeve and the outer diameter of the pipe is small. So it is much more easier for the sealing tighten and small torque is needed.

Dedicated flange adapters use an A type gasket(as below figure No.3) which is sized to fit the pipe so that only a small amount of torque is required to form a very good seal. Therefore, it is especially suitable for sealing large outside diameter pipes.